This application proposes to conduct a Stage II randomized trial to test Culturally Informed & Flexible Family-Based Treatment for Adolescents (CIFFTA) a treatment developed as part of a Stage I treatment development effort and showing very promising preliminary findings. Drug use rate are highest among Hispanic middle school youth and to date there are few if any treatments that have been proven effective with substance abusing Hispanic adolescents. Further treatment for Hispanic youth and families is complicated by the fact that these families often differ from mainstream drug users in values, beliefs and behaviors that can directly impact engagement, retention, and efficacy/effectiveness of drug treatment. Our efforts to develop and fully test a more powerful treatment that can address these issues began with a Stage 1 study that: 1) led to the development of a flexible manual that allows treatment tailoring to the unique family characteristics, 2) showed highly promising feasibility and acceptability indicators (Santisteban and Mena, in press) and 3) showed highly promising preliminary outcomes on both drug use and family-level hypothesized mediators (Santisteban et al., unpublished manuscript). This application proposes a Stage II randomized trial with 220 Hispanic youngsters' ages 14-17 meeting criteria for drug abuse and their families. The study will test the treatment's efficacy compared to a control condition, in impacting drug use, risky sexual behavior, and hypothesized mechanisms (family functioning and therapeutic alliance) of change, in a larger and more rigorous trial. The study also includes a test of the dose-response relationship and exploration of moderators of treatment outcome. This application responds to a Program Announcement (PA-07-111) that outlines as areas of interest ...women, minorities, families, couples, specific cultural groups, adolescents... The Stage II trial focuses on a treatment designed to boost the treatment effects by building in a flexible tailoring process to better address the specific needs of: 1) adolescents, 2) minorities and a special cultural group - Hispanics, via a treatment that works with 3) couples and families.